This invention relates in general to excavation equipment and in particular to a new and useful round link chain particularly for a single chain belt for scraper chain conveyors.
The invention particularly concerns a round link chain, particularly a single chain belt for chain scraper conveyors, with vertical and horizontal links, both having chain link sides and chain link arches joining the sides, and the vertical links having flattened exterior chain link sides.
A round link chain for mining conveyors and especially middle chain scraper conveyors includes vertical links with a flattened cross section in contrast to a round cross section, but only at their parallel chain link sides, while the arches joining the sides have a round circular cross section. Furthermore, the vertical links have a constant cross section size, which is the same as the cross section size of the horizontal links, while the pitch of the vertical and the horizontal links is identical. A round link chain of this type should be suitable for use in chain scraper conveyors, particularly middle chain scraper conveyors with a rolling cam, even when rather large drive performance requires a thicker chain, while the vertical links cannot exceed the side profile of the conventional conveyor trough in either the carrying run or the slack run. In such cases where the height of the trough depends on the working of the mine and consequently the carrying run and the slack run are restricted in the height of the passage, it is no longer possible to use a normal round link chain with links sufficiently strong to withstand the greater traction forces. For this reason, twin middle chain conveyors have already been tried as a solution to the problem. The round link chain, however, is not free of drawbacks, inasmuch as the use of found link chains with stronger links also requires use of another chain starwheel or sprocket. For the pitch of the chain links changes with the thickness of the sprocket. On account of the identical pitch of the vertical and the horizontal chain links, which increases with larger chain thickness, it is necessary to use sprockets with a different, that is, a larger pitch diameter. This, again, calls for a modification or even a replacement of a machine frame built onto the dump end of a chain scraper conveyor to provide for the mounting of the sprocket.
In another application, that is, the guiding of a coal cutting machine which spans the trough of a chain scraper conveyor as a gantry, the drive unit arranged ar the gob end has a chain wheel engaging with a round link chain, the chain being laid in a runner section with engagement slots for the wheel. The round link chain includes long horizontal links and short vertical links, the clear pitch of the vertical links up to a predetermined free motion corresponding to twice the diameter of the horizontal links. This is supposed to substantially exclude a pulling apart or pushing together of the chain links, and a proper pitchwise meshing of wheel and chain is even achieved when the chain scraper conveyor travel over saddles, declivities or curves and is used at a steep or semi-steep stratum. These known measures, however, do not affect the problems, mentioned at the outset, concerning the use of round link chains to take up larger traction forces.